Fortran Wiki
atomic_add

Description

atomic_add(atom, value) atomically adds the value of var to the variable atom. When stat is present and the invocation was successful, it is assigned the value 0. If it is present and the invocation has failed, it is assigned a positive value; in particular, for a coindexed atom, if the remote image has stopped, it is assigned the value of iso_fortran_env‘s stat_stopped_image and if the remote image has failed, the value stat_failed_image.